The U.S. State Department has summoned Turkish Ambassador in Washington Serdar Kılıç on May 17 over a street brawl outside the Turkish diplomatic mission that erupted between protesters and Turkish security personnel during President Recep Tayyip Erdoğan's visit, sources have told the Hürriyet Daily News.

On May 17, the United States voiced its "strongest possible" concern to Turkey over the street brawl that left at least 11 people injured and appeared to include members of Erdoğan's security detail kicking people who were on the ground.

The State Department condemned the attack as an assault on free speech, issuing a statement to express its concern regarding the violence outside the Turkish ambassador's residence.

"Violence is never an appropriate response to free speech, and we support the rights of people everywhere to free expression and peaceful protest," said the statement, clearly stating that the demonstration in front of Kılıç's residence was legal, peaceful and protected.

The statement said that the U.S. communicated its concerns to the Turkish government "in the strongest possible terms."

Eleven people were injured, including a police officer, and nine were taken to a hospital, Metropolitan Police Chief Peter Newsham said at a news conference on May 17.

The Turkish embassy released a statement on May 17 that contradicted U.S. officials and video evidence, blaming instead the demonstrators, who, it said, had been "aggressively provoking Turkish-American citizens who had peacefully assembled to greet the president."

A group of Republican lawmakers called the incident an "affront to the United States" and called for Turkey to apologize.

Meanwhile, U.S. Senator John McCain, one of the leading foreign policy voices in Congress, on May 18 urged the expulsion of Turkey's U.S. ambassador after violence erupted between protesters and Turkish security personnel during President Recep Tayyip Erdoğan's recent visit.

"We should throw their ambassador the hell out of the United States of America ... This kind of thing cannot go unresponded to diplomatically," McCain, the head of the Senate Armed Services Committee, told MSNBC in an interview on May 18, adding that legal action could also be pursued.

The U.S. Senator had earlier called the brawl "thuggish behavior."

"This is the United States of America. We do not do this here. There is no excuse for this kind of thuggish behavior," McCain said on his Twitter account.